A military explosives team detonated a suspected mine that a diver discovered partially buried in the sand in the ocean off a New Jersey beach.
A four-member explosive ordnance disposal team assigned to Naval Weapons Station Earle in Colts Neck examined it after the diver made the discovery on Tuesday night.
The team decided the only safe thing to do was to detonate it in place at high tide Wednesday.
A boom echoed through the small town and a plume of water rose about 125 feet into the air when the device was detonated.
The team then went back in the water to make sure no explosives were left behind.
The device was believed to be a contact mine from either World War I or World War II, base public affairs officer Michael Brady said. But it was not known whether there were explosives inside or if it was just used for training.
The device was partially buried in sand in the Atlantic Ocean off a northern New Jersey beach.
Police evacuated about 15 homes in a quarter-mile radius Wednesday, Bay Head police Sgt. Todd LaRue said. The Coast Guard kept boats clear of the area.
Superstorm Sandy may have exposed the device, Brady said. The explosives team has responded a half-dozen times to similar incidents since the storm hit the Jersey shore on Oct. 29, but mainly to the north near Sea Bright and Sandy Hook.
Sandy Hook was used as a military proving ground for explosives between 1874 and 1919.
While startling to some, the discovery of old munitions on Jersey shore beaches or just offshore is not all that unusual. The military has said it dumped large quantities of munitions overboard at the end of both World Wars as the conflicts were ending.
In 2007, more than 1,000 pieces of World War I and World War II-era munitions were discovered on the beaches of Long Beach Island after they were unwittingly sucked up by dredges and pumped ashore as part of a massive beach replenishment project.
Similar discoveries have been made off the coasts of Delaware and New York.
In 2007, the U.S. Army Corps of Engineers recovered 1,080 pieces of material, including fuses and other military hardware, from Surf City and Ship Bottom that were unearthed as part of the beach project.
Merchants rushed to capitalize on the unwanted publicity by selling T-shirts with slogans including, "Our Beaches Will Blow You Away" and "I Got Bombed On Long Beach Island."